Abstract: To enable the drivers to see the tunnel portal early, adapt to environmental changes early, and make driving decisions early, the sight distance, sight zone, and traffic safety in the tunnel entrance sections are analyzed, a concept of linear guiding system is established using common linear visual guiding facilities such as retroreflective rings, retroreflective strip, and elastic traffic column, and the improving methods in tunnel entrance sections based on linear guiding are proposed. Additionally, the data of gaze position at daytime and nighttime are collected through indoor simulation tests, and the fixation zone is divided into 5 categories to analyze the visual transfer characteristics of the gaze points in each zone and evaluate the effect before and after the improvement of the tunnel entrance zone. The results reveal the following: (1) The linear guiding system in tunnels has the characteristics of diverse forms, large size, prominent contour, and scattered light, which can improve the safety of tunnel lighting at a low cost. (2) Before the tunnel entrance zone is improved, the drivers′ gaze points probably appear near the front. (3) After the improvement, the drivers′ gaze points probably appear far ahead, indicating that the improvement scheme makes the drivers′ sight distance sufficient. The change of fixation probability in the main distribution zone of fixation points after improvement is more moderate than that before improvement, indicating that the change of drivers′ sight zone has been alleviated.

Key words: highway tunnel, entrance, linear guiding system, sight distance and sight zone, visual transfer